code: def onBars(self, bars):
      bar = bars[self.__instrument]
      self.info(
          "Price: %s. Volume: %s." % (bar.getClose(), bar.getVolume())
      )
  
file_path: pyalgotrade/samples/tutorial_twitter_bitstamp.py
imports: from pyalgotrade import strategy
  from pyalgotrade.bitstamp import barfeed
  from pyalgotrade.bitstamp import broker
  from pyalgotrade.twitter import feed
label_desc: Use image node_id 3 for calling the Strategy obj's underlying member method code with example usage: obj.onBars(bars) without return types